Meandering River

Braided rivers are relatively simple to produce in the laboratory, whereas dynamic meandering rivers have not been sustained beyond initial bend formation. Meandering is theoretically explained by bend instability growing from planimetric perturbation, which convects downstream. In this study, we experimentally tested the importance of upstream perturbation and chute cutoff development in the evolution and dynamics of a meandering channel pattern. The initial straight channel had a transversely moving upstream inlet point and silt-sized silica flour was added to the sediment feed to allow floodplain formation. We obtained a dynamic meandering river with scroll bars. Bend growth was alternated by chute cutoffs that formed across the point bars. Meandering was maintained as one channel was disconnected by a plug bar. The curvature at the chute bifurcation transported sediment and build a new floodplain, while the other channel widens. At the end of the experiment, the fluvial plain exhibited a meandering channel, point bars, chutes and abandoned and partially filled channels with a slightly cohesive floodplain surface similar to natural meandering gravel-bed rivers. We conclude that the necessary and sufficient conditions for dynamic meandering gravel-bed river are a sustained dynamic upstream perturbation and floodplain formation.

This research deals with the surface dynamics and key factors –
hydrological regime, sediment load, and erodibility of floodplain
facies – of frequent channel shifting, intensive meandering, and
lateral instability of the Bhagirathi River in the western part of the
Ganga-Brahmaputra Delta (GBD). At present, the floodplain of
the Bhagirathi is categorized as a medium energy (specific stream
power of 10–300 W m−2), non-cohesive floodplain, which exhibits a
mixed-load and a meandering channel, an entrenchment ratio >2.2,
width–depth ratio >12, sinuosity >1.4, and channel slope <0.02. In
the study area, since 1975, four meander cutoffs have been shaped
at an average rate of one in every 9–10 years. In the active meander
belt and sand-silt dominated floodplains of GBD, frequent shifting
of the channel and meander migration escalate severe bank erosion
(e.g. 2.5 × 106 m3 of land lost between 1999 and 2004) throughout the
year. Remote sensing based spatio-temporal analysis and stratigraphic
analysis reveal that the impact of the Farakka barrage, completed in
1975, is not the sole factor of downstream channel oscillation; rather,
hydrogeomorphic instability induced by the Ajay–Mayurakshi fluvial
system and the erodibility of floodplain sediments control the channel
dynamics of the study area.

Includes only chapter 1 and 7, see other chapters main page.

Rivers have distinctive channel patterns such as multi-channel braiding and single-channel meandering. Why these different river patterns emerge is only qualitatively understood. Yet, we have not been able to retain dynamic meandering in laboratory experiments. The main objective of this thesis was to develop experimental settings in the laboratory that lead to dynamic meandering, in order to determine how rivers self-organize their morphology through interactions between channels, floodplain and vegetation. I unraveled these interactions in a series of controlled flume experiments. I found that classical similarity scaling as used in engineering scale models does not work well because the channel width-depth ratio that determines bar formation is a dependent parameter in self-formed channels. Therefore, I relaxed the scaling rules. Systematic small-scale tests showed that there is a narrow range of suitable conditions for continuous meandering regarding sediment mobility and bank strength. Initially, in a straight channel with a low width-depth ratio alternate bars develop and evolve into meander bends. An upstream perturbation is required to initiate bar formation, but the experiments showed that a static perturbation led to low amplitude bends. In contrast, a transversely moving inlet point caused high-amplitude dynamic meandering with scrolls bars and infrequent chute cutoffs. Floodplain development further defined the resulting river pattern. In experiments with only channel sediment, overbank flow led to chute cutoffs that terminated meander bend development and that were the onset of a braided river with multiple parallel channels. Bank erosion by bend migration is balanced by deposition of sediment forming new floodplains and cutoffs, as also confirmed by numerical modeling. I showed that vegetation and fine sediment on the floodplain decreased the number of chute cutoffs, allowing meander bends to grow further. The fine sediment adds cohesion to the floodplain and increased bank strength, while plants increased bank strength and roughness. The combination of flume experiments and numerical model results shows that channel dynamics are controlled by bankfull discharge conditions, but overbank flow is highly important in constructing and destroying the floodplain. The composition of the floodplain, e.g. cohesion of the banks and the presence of vegetation, determines whether a braided or a meandering river pattern develops.

Field studies suggest that a cohesive floodplain is a necessary condition for meandering in contrast to braided rivers. However, it is only partly understood how the balance between floodplain construction by overbank deposition and removal by bank erosion and chutes leads to meandering. This is needed because only then a dynamic equilibrium exists and channels maintain meandering with low width-depth ratios. Our objective is to understand how different styles of floodplain formation such as overbank deposition and lateral accretion cause narrower channels and prevent chute cutoffs that lead to meandering. In this study we present two experiments with a self-forming channel in identical conditions, but to one we added cohesive silt at the upstream boundary. The effect of cohesive silt on bank stability was tested in auxiliary bank erosion experiments and showed that an increase in silt reduced erosion rates by a factor of 2. The experiment without silt developed to a braided river by continuous and extensive shifting of multiple channels. In contrast, in the meandering river silt deposits increased bank stability of the cohesive floodplain and resulted in a reduction of chute cutoffs and increased sinuosity by continuous lateral migration of a single channel. Overbank flow led to deposition of the silt and two styles of cohesive floodplain were observed; first, overbank vertical-accretion of silt, e.g. levee, overbank sedimentation or splays; and second, lateral point bar accretion with silt on the scrolls and in the swales. The first style led to a reduction in bank erosion, while the second style reduced excavation of chutes. We conclude that sedimentation of fine cohesive material on the floodplain by discharge exceeding bankfull is a necessary condition for meandering.

Although fundamental types of fluvial meander-bend transformations – expansion, translation, rotation, and combinations thereof – are widely recognised, the relationship between the migratory behaviour of a meander bend, and its resultant accumulated sedimentary architecture and lithofacies distribution remains relatively poorly understood. Three-dimensional data from both currently active fluvial systems and from ancient preserved successions known from outcrop and subsurface settings are limited. To tackle this problem, a 3D numerical forward stratigraphic model – the Point-Bar Sedimentary Architecture Numerical Deduction (PB-SAND) – has been devised as a tool for the reconstruction and prediction of the complex spatio-temporal migratory evolution of fluvial meanders, their generated bar forms and the associated lithofacies distributions that accumulate as heterogeneous fluvial successions. PB-SAND uses a dominantly geometric modelling approach supplemented by process-based and stochastic model components, and is constrained by quantified sedimentological data derived from modern point bars or ancient successions that represent suitable analogues. The model predicts the internal architecture and geometry of fluvial point-bar elements in three dimensions. The model is applied to predict the sedimentary lithofacies architecture of ancient preserved point-bar and counterpoint bar deposits of the middle Jurassic Scalby Formation (North Yorkshire, UK) to demonstrate the predictive capabilities of PB-SAND in modelling 3D architectures of different types of meander-bend transformations. PB-SAND serves as a practical tool with which to predict heterogeneity in subsurface hydrocarbon reservoirs and water aquifers.

Özet İnsanların suya olan gereksinimlerinden dolayı insanlığın tatlı su kaynakları etrafında yeşermiş olduğu, kültür ve medeniyetin akarsu havzalarında ortaya çıktığı görüşü belirgin bir genellemedir. Bu bağlamda akarsulara çağlar boyu büyük bir önem bazen de kutsiyet atfedilmiştir. Antikçağ yazarları da bu konuya sıkça değinmişler ve akarsuları eserlerine konu etmişlerdir. Pseudo-Plutarkhos da Nehirler Üzerine adlı eserinde ağırlıklı olarak nehirleri konu edinmiş ve nehirler hakkında okuyucuya bazı bilgiler vermeye çalışmıştır. Pseudo-Plutarkhos'un konu edindiği nehirlerden biri de Maiandros (Büyük Menderes Nehri)'tur. Antikçağda Phrygia Bölgesi'ndeki Kelainai yakınlarından kaynağını almış olan Maiandros sözü edilen bölge boyunca akmış daha sonra Lydia, Karia ve Ionia bölgelerinin arazilerini sulayarak Aigaios Pontos'a (Ege Denizi) dökülmüştür. Uzunluğu ve taşıdığı suların bolluğuyla antikçağ Asia'sının (Küçük Asya) en büyük nehri olarak görülmüş, içinden geçtiği coğrafyaları şekillendirmiş ve sağladığı imkanlarla o bölgelere hayat vermiştir. Maiandros Nehri'nin akıntısının zikzaklı olması son derece ilgi çekici olmuş, antikçağ yazarlarının nehre faklı anlamlar yüklemesine ve antikçağ insanının zihninde farklı imgelemler oluşmasına neden olmuştur. Zikzaklar çizen her nehir ya da zikzaklı olan her şey onun adıyla anılmaya başlamıştır. Nehrin akış şeklini esas alan bir bezeme motifi dahi oluşturulmuş ve nehrin adıyla özdeşleştirilmiştir. Bu çalışmada Pseudo-Plutarkhos'un sözü edilen eseri hakkında kısa bir değerlendirme yapıldıktan sonra yazarın anlatılarına istinaden, nehrin isminin kökeninden, akış rotasına, aktığı güzergahtaki yörelere sağladığı yarardan neden olduğu zararlara ve antikçağdan günümüze ulaşan etkilerine değinilmiştir.

This paper is an extension and continuation of an earlier work by the authors on the phenomenon of meandering in Al-Abbasia reach located in the middle of the Euphrates river, Al-Najaf governorate in Iraq. The authors have developed several power functions and models depending on dimensional analysis and Buckingham π-theorem for modeling and predicting the hydraulic geometry of the selected reach. The paper employs the non-linear regression technique for developing mathematical models for computing the width and mean depth of the reach depending on its hydraulic characteristics. This paper is part of an M. Sc. thesis carried out in 2014. The developed relationships are straightforward to be applied in design and analysis with results of high acceptability; the reach width (W) model has an R2 of 0.97, while the reach mean depth (Dm) model has an R2 of 0.93. Different statistical methods have been utilized to compare the different models. The results reveal that non-linear regression ...

Rivers are significant geomorphic agents which can carry huge amounts of sediments and water from their catchments to depositional basins. Due course of flow they can bring various hazards such as flooding, inundation of flood plains, erosion of banks and trigger various slope movements. To understand nature and behavior of the Bagmati River, which is a perennial, storm and spring-fed, eight order river of central Nepal, the planiform morphological parameters of this river were analysed and river segments along the main stem stretches were classified into various stream-types, using topographic maps, aerial photographs, and satellite imageries. The Bagmati River is an 8th order perennial river. The Bagmati River basin comprises 39 sub-basins of 4th order and higher. The averages of meander wavelengths (Lm), meander belt width (Wblt), radius of curvature (Rc) and sinuosity (K) of the 7th order main stem Bagmati River are 598.27 m, 164.07 m, 252.35 m and 1.38, respectively. Similarly,...

La planicie aluvial del río Portoviejo es parte de un sistema geomorfológico fluvial dinámico que, ha experimentado cambios espaciales en el tiempo y sobre ellos, la acción humana ha sido cada vez más influyente y determinante. Uno de los aspectos necesarios para comprender este complejo esquema evolutivo, además de conocer el comportamiento hidrológico de la cuenca y de sus aspectos geomorfológicos, es el análisis de la dinámica espacio-temporal del canal principal del río en diferentes períodos y, a lo largo de su recorrido en la llanura aluvial, pues ello guarda relación con la movilidad de los escenarios de inundaciones. Los parámetros geométricos del canal principal de un río son muy sensibles a experimentar cambios, como consecuencia de intervenciones antrópicas o de la intensificación de las mismas así, como también, cambios en los patrones de meandros, debido a la carga de sedimentos y a las afectaciones en la geometría del canal. Debido a ello, es propósito de este trabajo, analizar los cambios espacio-temporales de los patrones de meandros del canal principal del río Portoviejo en su planicie aluvial, mediante el análisis de los parámetros morfométricos de sus patrones de meandros. La metodología de trabajo consistió en la revisión y análisis de informes técnicos, imágenes de satélite de Google Earth, cartografía base de la temática existente y observaciones de campo, a partir de las cuales se realizaron fotointerpretaciones de los patrones de meandro y, una matriz de información detallada. Se realizó un muestreo en cada patrón de meandros, para los distintos períodos considerados en el estudio, sobre los cuales se cuantificaron los siguientes parámetros geométricos: longitud del cuello de meandro (L), longitud del eje (A), ancho del meandro del río (W), radio de la curvatura (R), longitud de la curvatura (S) y sinuosidad (C). Los resultados muestran de manera preliminar que, la variabilidad espacio-temporal más significativa de los meandros se observa en el tramo entre las localidades de Colón y Ciudadela Nuevo Portoviejo, correspondiente a áreas con asentamientos poblacionales no planificados y, con intensificación de actividades antrópicas. En este segmento del río se aprecian cambios importantes en la posición de los meandros, determinados por procesos de migración, estrangulamiento o acortamiento, los cuales se expresan considerablemente en la variabilidad de los valores del R. Por el contrario, en el tramo del río, correspondiente al área consolidada de la ciudad de Portoviejo, no se perciben variaciones considerables, lo que define un patrón meandriforme.

This paper is intended to reveal the absurdity of some alleged "progressive" attempts to alter well-tried-and-true beliefs in a deity,  to the extent that all they really achieve is an inconsistent kowtowing to overt feminism, assorted gender issues, misconstrued understanding of alleged `indigenous rights'  ad nauseam

Schrödinger fabricated an analogy to illustrate to the lay person how the Schrödinger Equation applies to the state of being of an endangered cat, despite the fact that the cat and the killing-device are in no way comparable to a pair of contiguously-created objects

Schrödinger did not wish to promote the idea of dead-and-alive cats as a serious possibility. On the contrary, he intended the example to illustrate the absurdity of the existing view of quantum mechanics, thus opening the opportunity to bring on the investigation of its worth via the argument `Reductio ad absurdum'.

However, some fellow physicists regarded the `alive and dead' cat superposition as quite real. Intended as a critique of the Copenhageninterpretation (the prevailing orthodoxy in 1935)

A paradigm is a model for the purpose of explaining an event, existent and/or a belief, which may be expressed solely in words, solely in equations or a combination of both.

It should be remembered, however, that any paradigm is an objective, (theoretical, epistemic), attempt to explain an observed phenomenon, [which, in itself, is subjective, (existential, ontic)] and therefore said phenomenon can be described by more than one paradigm, designed for the purpose of modelling it.

Often, the adherents/advocates to/of a particular paradigm have `one-track' minds, and are resistant to the suggestion of considering a paradigm shift, despite the obvious need for taking that step into "Critical Thinking".

The two best-known number sequences, recursive over the two previous terms, are Fibonacci and Lucas.  There are at least 5 ways of defining them:-
e.g. 1) Each term is the sum of the previous 2 terms etc..
        2) An equation, which determines the (n+1)th term.
        3) The sum to the (n+1)th term.
        4) The limiting value of the ratio of two successive terms.
      5) The generating function.
    All these types of series can be treated under the one generalisation, called a General Admixture Series, (G.A.S.), 

Download all DNL-DERIVE- and TI-files from
http://www.austromath.at/dug/

El río Portoviejo a lo largo de su recorrido ha experimentado una serie de cambios geomorfológicos en sus patrones de meandros, producto de la interrelación entre factores naturales propios de la morfodinámica fluvial de su cuenca, y factores antrópicos prolongados y crecientes en su planicie aluvial. Desde esa perspectiva, en este trabajo se analizan, bajo un enfoque cuantitativo, los procesos geomorfológicos-evolutivos que controlan los cambios espaciales en tres patrones de meandros de la planicie aluvial del río Portoviejo. La metodología desarrollada contempló: (a) análisis estadístico descriptivo para los meandros correspondientes a cada uno de los patrones (segmentos) y según sus parámetros morfométricos; (b) construcción de curvas evolutivas de los meandros de cada segmento en atención a cada parámetro morfométrico; (c) análisis comparativo entre patrones de meandros para cada uno de los años considerados en el período de estudio y por cada parámetro morfométrico; y (d) análisis Biplot Dinámico desarrollado mediante el modelo HJ-Biplot. Los análisis estadísticos fueron desarrollados con los software InfoStat y Rstudio. El análisis estadístico descriptivo reveló que existen amplias diferencias geométricas entre meandros de un mismo segmento, lo que evidencia una movilidad espacio-temporal distinta entre ellos; y entre los segmentos de meandros, indicando un control diferencial de los factores que condicionan la génesis y evolución de cada patrón. Los resultados del Hj-Biplot estático permitieron ver la relación entre los parámetros morfométricos y los meandros por cada segmento o patrón. Se observó que los parámetros R, L y S están correlacionados entre sí, mientras que, las correlaciones negativas entre los parámetros W y C, no son significativas. El análisis dinámico, aparte de exhibir la relación existente entre los parámetros morfométricos, muestra las variaciones de los meandros según esos parámetros a lo largo del período estudiado, observándose que para algunos casos existen variaciones importantes y, para otros, no son muy significativas.

Fractals and their Basin of Stability

Hans Lauwerier(*) outlined a method to predict the Cardioid basin arising from the iteration of the Circle in the Mandelbrot fractal, however he left it at the one example, therefore the generalisation of the approach begs investigation

REDUCTIO AD ABSURDUM (OR NOT?)

INGREDIENTS FOR AN IDEAL PARADIGM

Whereby, one postulates a major premise for a mathematical model of a hypothetical universe, and assumes it to be true, then follows it with a minor premise, which is known to be true, then a logically valid conclusion arises for one to compare and correlate with known observations in the actual universe.
A concatenation of derivative syllogisms can follow on and, providing no cognitive dissonance(s) arise(s), then the RST model may prove to be a viably functional, and therefore a competing, paradigm for the modelling of the physical universe. (e.g. RST)

Present paper deals with the study of a meander in River Barak around Silchar town in Assam using remote sensing and GIS, encompassing a period of thirty-four years between 1976 and 2010. Changes in planform characteristics of River Barak are analysed with the help of six remote sensing images of the years 1976, 1979, 1988, 1999, 2003, and 2010. The sinuosity of the meander is observed to be quite high (&gt;2.3) exhibiting a decreasing trend in thirty-four years. The meander ratio ranging from 1.05 to 1.12 also exhibited a decreasing trend. The decreasing trends of sinuosity and meander ratio undermine the probability of cut-off across the meander in near future. To analyse the meander shift, three Ground Control Points (GCPs) were selected. It is observed that the western arm of the meander bend around Silchar town has shifted about 132.45 m towards northwest while the eastern arm of the bend has shifted about 61.59 m towards east and 9.88 m towards northwest at two locations respe...

В статье выявлена взаимосвязь выбросов энергии в пространстве речных излучин со строительством объектов культового назначения (О.К.Н.) на территории Месопотамии и Египта. На примере гидротопографии Древнего Вавилона, его окрестностей (Борсиппа), а также Древнего Египта раскрыта закономерность в месторасположении ряда известных культовых сооружений. По мнению автора, существует прямая зависимость между локализациией О.К.Н. и особенностями местной гидрографии. Кроме того, в работе были произведены расчеты основных
физических параметров импульсного (энергетического) воздействия в речных излучинах / The article reveals the relationship between energy releases in the space of river bends and the construction of religious-purpose
objects within the territory of Mesopotamia and Egypt. By the example of the hydrotopography of Ancient Babylon, its environs
(Borsippa), and also of Ancient Egypt, the study reveals regularity in the location of a number of famous religious buildings.
In the author’s opinion, there is direct relationship between the localization of religious-purpose objects and the features of local
hydrography. In addition, the calculations of the main physical parameters of impulse (energy) effect in river bends are made.

Abstract This research deals with the surface dynamics and key factors – hydrological regime, sediment load, and erodibility of floodplain facies – of frequent channel shifting, intensive meandering, and lateral instability of the Bhagirathi River in the western part of the Ganga-Brahmaputra Delta (GBD). At present, the floodplain of the Bhagirathi is categorized as a medium energy (specific stream power of 10–300 W m−2), non-cohesive floodplain, which exhibits a mixed-load and a meandering channel, an entrenchment ratio &gt;2.2, width–depth ratio &gt;12, sinuosity &gt;1.4, and channel slope &lt;0.02. In the study area, since 1975, four meander cutoffs have been shaped at an average rate of one in every 9–10 years. In the active meander belt and sand-silt dominated floodplains of GBD, frequent shifting of the channel and meander migration escalate severe bank erosion (e.g. 2.5 × 106 m3 of land lost between 1999 and 2004) throughout the year. Remote sensing based spatio-temporal analysis and stratigraphic analysis reveal that the impact of the Farakka barrage, completed in 1975, is not the sole factor of downstream channel oscillation; rather, hydrogeomorphic instability induced by the Ajay–Mayurakshi fluvial system and the erodibility of floodplain sediments control the channel dynamics of the study area.

ABSTRACT Recent studies suggest that braided river could be single-thread channel by colonization of riparian vegetation; however, this kid of mutual interactions between physical and ecological processes in rivers are still poorly understood. Here we investigate the development of meandering channel in a river, which was originally braided and currently vegetated, the Otofuke River in Japan. The significant morphological processes of this river during a destructive flood event was studied using a two-dimensional morphodynamic model. Using well-calibrated parameters, this model qualitatively reproduced observed morphological changes such as the co-development of sand bars, bar-induced meandering and a chute cutoff. We find that for vegetated channels, meandering could maintain moderate sinuosity; in contrast, in the absence of riparian vegetation, bar-induced meandering channels could become braided. This suggests that distinct meandering channels could be a fundamental channel morphology in the originally braided, but currently vegetated river; however, the simultaneous occurrence of the chute cutoff and meandering indicates that this channel could not be a fully-developed high amplitude meandering channel.

This paper is an extension and continuation of an earlier work by the authors on the phenomenon of meandering in Al-Abbasia reach located in the middle of the Euphrates river, Al-Najaf governorate in Iraq. The authors have developed several power functions and models depending on dimensional analysis and Buckingham π-theorem for modeling and predicting the hydraulic geometry of the selected reach. The paper employs the non-linear regression technique for developing mathematical models for computing the width and mean depth of the reach depending on its hydraulic characteristics. This paper is part of an M. Sc. thesis carried out in 2014. The developed relationships are straightforward to be applied in design and analysis with results of high acceptability; the reach width (W) model has an R2 of 0.97, while the reach mean depth (Dm) model has an R2 of 0.93. Different statistical methods have been utilized to compare the different models. The results reveal that non-linear regression ...

Researching the behavior of the river. Especially at the bend, where the morphology of the river is not always straightforward. Flow velocity high water and grinding at river bends occur at different points. This research was conducted on five adjacent bends on the Sidoan River section. This study examined the condition of riverbed sediment, knowing the stability of riverbed sediment granules based on shearing velocity, and stability of riverbed sediment granules based on shear stress. The method used in this study is geometric measurement. Q 50 discharge calculation. produces hydraulic simulation. d 50 sediment diameter. HEC-RAS software simulation and Shields graphs analysis. The results of the study on five bends for Q 50 discharge are the condition of the riverbed in five bends all moving, the critical shear velocity relationship and flow depth are directly proportional, the highest condition at bend 2, otherwise the lowest condition at bend 3. The relationship between particle dimensions and shear velocity is inversely proportional to the value of sliding velocity. if the particle dimensions are small then the large shear stress occurs at bend 5 and vice versa, the dimensions of large particles then the small shear velocity occurs at bend 4, sliding velocity is directly proportional to the shear stress. The highest critical shear stress at bend 2, while the lowest condition at bend 4, the greater the radius of the bend the scouring was deeper.

The Upper Triassic succession in S Poland in which dinosaur bones have been found consists predominantly of siltstones and claystones. Three units are distinguished. The lowermost and the uppermost units reflect an alluvial environment, whereas the middle one represents lacustrine facies. The lower alluvial unit is interpreted as a record of ephemeral, sinuous, suspended-load channels with rapid vertical accretion. Channel barforms are lacking. The environment is interpreted as a low-energy anastomosing fluvial system. The clayey middle unit is interpreted as having formed in a wide long-lived lake. The top of the lacustrine deposits shows signs of vertisol-type pedogenesis, most probably under subtropical conditions, with seasonally-induced wet and dry intervals. The upper unit reflects a low-energy meandering river system. Silty point bars were abundant and the channels migrated freely. The energy level of this fluvial system was slightly higher than that of the earlier one, which...

"On the continuous migrating of meander bends

W.M. van Dijk1, W.I. van de Lageweg1, F. Schuurman 1 and M.G. Kleinhans 1
1 Faculty of Geosciences, Department of Physical Geography, Utrecht University, PObox 80115, 3508 TC, Utrecht, The Netherlands

Explanation and prediction of dynamic river meandering has been a topic of scientific research for multiple decennia and still forms a major challenge for river management. River meanders grow and migrate by bank erosion, whilst constant channel width is maintained by floodplain formation. Meander amplitude is restricted by cut-offs, restoring low amplitude meanders. Meandering is thought to originate from bend instability, starting with small perturbations in channel curvature that lead to erosion in outer bends. However, in experiments and 2D/3D computer models to date, dynamic meandering never sustained beyond initial bend formation as the single-thread channel evolved into a braiding system. As showed by Lanzoni and Seminara (2006), initial perturbation is insufficient to maintain a meandering channel, due to downstream migration of the meander bends.
Our objective was to understand the necessary conditions for continuing meander migration, using long-term flume experiments and morphodynamic modeling. Two novel methods have been applied, related to upstream channel migration and floodplain formation.
We performed flume experiment and numerical modeling, using the simplest possible conditions with constant discharge, constant base-level, straight initial channel and uniform bed slope. In order to keep the channel actively meandering, the upstream inflow is harmonically moved in lateral direction, mimicking the presence of actively meandering bends upstream of the investigated channel reach. For the numerical modeling, the 2D-depth averaged morphodynamic model Nays2D (Dulal et al., 2010) was used. The flume experiments were executed in the 11 x 6 m Eurotank of the Utrecht University (Van Dijk et al., 2012).
Long-term dynamic meanders were produced in both flume experiments and numerical modeling. Initially, small free bars formed along the entire channel in the model and flume. Migration of the upstream channel to the left triggered the formation of a meander. When the upstream channel reversed migration in transverse direction, meander migration accelerated and multiple consecutive high sinuosity meander bends arose in the model. During the runs the channel width-depth ratio maintained as floodplain-formation countered bank erosion. Without a lateral migrating upstream boundary, no meander bends formed, retaining a straight channel in experiments and model runs. Lateral movement of the upstream inflow resulted in continuously active meander migration, with several cycles of bend growth and cut-offs.
We conclude that continuously meander migration can be achieved by continuous upstream bend instability. Also, floodplain formation is a key process for retaining a single-threaded channel.

References
van Dijk, W.M., W.I. van de Lageweg, M.G. Kleinhans (2012) Experimental meandering river with chute cutoffs. Journal of Geophysical Research, 117, F03023.
Dulal, K.P., K. Kobayashi, Y. Shimizu, G. Parker (2010) Numerical computation of free meandering channels with the application of slump blocks on the outer bends. Journal of Hydro-environmental Research, 3, 239-246.
Lanzoni, S., G. Seminara (2006) On the nature of meander instability. Journal of Geophysical Research, 111, F04006.
"

Source Doc: https://alternate-logic.blogspot.com/2022/07/for-your-conscious-intent-you-do-get.html



For your conscious intent, You DO 'get what you deserve'!

See link for this image:  'Why We Fail and How'

Not that your intent is validated as good or bad, or that the results will, being favorable or unfavorable, are ethical and spiritually moral. It means in the context of your motivating preconceptions, you've gotten what you deserve!

When You're going by your own rules-just pulling them out of your intuitive, ass' notions of obsessions and imperatives-there will be mechanical adjustment other than being more accommodating or conformist to what you decided from which to deviate. There are some hard realities you'll encounter that will necessitate a new perspective or incidental fine-tuning. That which particularly seems like FAILURE or success may have more to do with the perspective and expectations of intent.

In "failure", though one door seems to be slammed shut in your face, if you take a moment to step back, turn around, and see the broader scope about you, that failure just might have been the liberating forced leverage you needed for your 'Self' to open your eyes to other means and factors that your preconceptions had not counted on.

Being an intuitive Iconoclastic thinker from the herd-of-thought is a meandering, convoluted, marathon path, than a sprint or short run from point A-to-point B. It's a thought deconstruction and reconstruction of your minds soft-ware and embedded hardware of habits. This will take the time and discipline which you randomly ignored and discounted, prior to this off-the-beaten-path journey.

It's about your juxtaposition with an idea, for which relationships with people come to be seen as passing ephemerals and transactional incidentals. People are just the symbolic props of place and time than the long-sought soul-mate of longevity. The mechanics of your thinking are your bestie, your partner, your companion-literally and figuratively.

Make friends with your mind's mechanics and its minimalist, obligatory and imperative needs in the most expedient, amoralistic ways, when necessary, to nurture and develop the path your mind's mechanics present to your conscientious discernment.

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Rivers is one of the complex natural systems. Classification of the river plan change is very important to know the river problems in early stage, where the classification database can help to understand the behavior of the river in each part. This article discusses about the classification of river plan change at the mainstream of Pahang River, Malaysia. Based on Geographical Information System (GIS) and Remote Sensing (RS) database, analysis of Types Of Lateral Activity (TYLAT) method and Modes of Meander Movement (MOME) method have been used to identify the evolution of the river plan change. The study results indicated, methods of TYLAT are more suitable to use for examining the evolution of river plan change for large and width rivers. While, method of analysis MOME index is more suitable for smaller types of rivers as the upper and middle reaches of the river. From this result, this study can be produced the basic information or database to understanding the characteristics or...